PROJECT SUMMARY Across the lifecourse, there are pronounced racial and economic disparities in important life outcomes in America, ranging from educational attainment to incarceration rates to physical health. Nonetheless, a substantial minority of African American youth who grow up under economic hardship achieves positive outcomes, a phenomenon termed resilience. Our research has recently revealed a paradox in the resilience literature. This literature often assumes that if at-risk youth manage to thrive in terms of observable behaviors, such as making it to college, then they have avoided the consequences of adversity. In contrast, we have identified a subgroup of youth who appear resilient on the surface via academic and behavioral indicators, but `under the skin' display signs of compromised physical health, such as higher risk of diabetes and higher scores on allostatic load (a multi-system indicator of chronic disease risk). These findings suggest that the same factors that help youth to succeed academically and psychosocially may be exacting a toll on them physically, resulting in resilience that is only `skin-deep.' Here we propose a project that will clarify why skin- deep resilience develops, when in development it emerges, and whether early-warning signs can be detected. We will recruit 450 African American youth from low-income families ages 14-19. They will be assessed at baseline and 1 and 2 years later, in the context of an accelerated longitudinal design (ALD). The first aim is to identify individual psychological and social network factors that contribute to skin-deep resilience, such as high levels of self-control that may promote academic success but have physiological costs, as well as a lack of belonging or experiences of discrimination with peers in academic environments among skin-deep resilient youth. The second aim is to create biological risk profiles that can function as early warning signs of developing health problems in African American youth. To that end, we will collect in-depth measures of stress hormone output, inflammatory activity, and epigenetic aging over a 2-year period, and test these markers' ability to predict subsequent cardiovascular risk, including metabolic syndrome (primary outcome) and flow- mediated vasodilation (an indicator of endothelial dysfunction; secondary outcome). The third aim is to determine when skin-deep resilience emerges and to characterize its developmental trajectory. To that end, we will use the accelerated longitudinal design to map skin-deep resilience, and its academic, psychosocial, and biological features across the high school and college years. Through this work, we will identify psychosocial targets for intervention, pinpoint optimal development windows for intervention, and highlight biological early warning signs, with the ultimate goal of preventing the emergence of chronic health conditions in low-income minority youth who are otherwise on a track to successful life outcomes.